Shock-absorbing mechanism for the viewing mirror of a single lens reflex camera

ABSTRACT

A shock-absorbing mechanism is provided for the viewing mirror of a single lens reflex camera. A spring-biased shock-absorbing lever having a pin or protuberance in the path of the mirror absorbs the impact forces. A spring-biased latch cooperation with the shock-absorbing lever latching the lever immediately before the mirror is moved into its raised position. The viewing mirror is thus moved to its raised position without impact.

United States Patent Inventor Sunao lshizaka Tokyo, Japan Appl. No.743,884 Filed July 10,1968 Patented Mar. 9, 1971 Assignee Nippon KogakuK. K.

Tokyo, Japan Priority July 18,1967

Japan 42/45813 SHOCK-ABSORBING MECHANISM FOR THE VIEWING MIRROR OF ASINGLE LENS REFLEX CAMERA 5 Claims, 5 Drawing Figs.

U.S. Cl 95/42 Int. Cl G03!) 19/12 Field of Search 95/42 (Inquired) [56]References Cited UNTTED STATES PATENTS 2,992,602 7/ 1961 Heden '95/423,468,232 9/1969 Knapp 95/42 Primary ExaminerSamuel S. MatthewsArsistant Examiner-Richard L. Moses Attorney-Anton J. Wille ABSTRACT: Ashock-absorbing mechanism is provided for the viewing mirror of a singlelens reflex camera. A springbiased shock-absorbing lever having a pin orprotuberance in the path of the mirror absorbs the impact forces. Aspringbiased latch cooperation with the shock-absorbing lever latchingthe lever immediately before the mirror is moved into its raisedposition. The viewing mirror is thus moved to its raised positionwithout impact.

Patented Mar ch 9, 1971 3,568,585

3 Sheets-Sheet 1 Patented March 9, 1971 3,568,585

3 sheets-sheet a Patented March 9,1971 3,568,585

3 Sheets-5het s SHOCK-ABSORBING MECHANISM FOR THE VIEWING MIRROR OF ASINGLE LENS REFLEX CAMERA This invention relates to a shock-absorbingmechanism for the viewing mirror of a single lens reflex camera.

The viewing mirror of a single lens reflex camera is moved into itsviewing position, usually at a 45 angle with the axis of the objectivelens, preparatory to the exposure of the film. A return mechanismcoupled with the shutter release, moves the mirror to its raised or homeposition an instant before the shutter is released. To move the mirrorout of the way quickly for film exposure, a force is required that leadsto impact and noise when the mirror abuts its stop in its raisedposition. The impact force of the mirror abutting its stop can cause aslight movement of the camera resulting in a blurred exposure. The noiseof such impact can also be very disturbing and even intrusive dependingupon the circumstances under which an exposure is made. v

In the past, various expedients have been tried to eliminate or at leastalleviate the mirror impact shock. Such expedients have not provensuccessful and cameras today of the single lens reflex type are stillprovided with small sponge or rubber bumpers as stops for the viewingmirror.

The object of the present invention is to provide a relatively simpleand efficient shock-absorbing mechanism for the viewing mirror of asingle lens reflex camera by which the shock of impact of the mirror isdissipated by a spring biased lever before the mirror is returned to itsraised position by the mirror return mechanism of the camera.

Another object of the invention is the provision of a collapsibleparallelogram linkage arrangement for raising and lowering the viewingmirror by the'mirror mechanism of the camera. I

According to the invention, the mirronactuating mechanism of the camerawill operate to raise and lower the viewing mirror in a manner known inthe art. Pivotably mounted within the mirror box or enclosure are twocooperating levers, a shock-absorbing lever and a latch lever. Each ofthe levers is spring biased, the shock-absorbing lever being biased in adirection opposite to the direction of travel of the mirror moving fromits viewing position to its raised position, while the latch'lever isbiased in the same direction as the direction of travel of the mirror toits raised position. With the mirror in. its viewing position, a pin onthe mirror is abutted by the latch lever. As the mirror is moved towardsits raised posi tion, it abuts a pin or extension fixed to the shockabsorbing lever and moves the lever against the bias of its springthereby absorbing the forces of movement of the mirror. As the mirrortravels towards its raised position, the latch lever is releasedpermitting its spring to move a detent into the path of movement of theshock-absorbing lever, the detent catching and holding theshock-absorbing lever just before the mirror moves into its raisedposition. The mirror moves against the stop provided for it with noimpact shock or noise.

In one embodiment of the invention, a parallelogram linkage system isprovided actuated by -the mirror-operating mechanism of the camera, themirror being pivotally mounted on one of the pivot points of thelinkage.

The invention both as to its organization and content, will be betterunderstood from the following detailed description when taken inconjunction with the annexed drawing, in

which: 7

FIG. 1 is a side elevational view with portions in cross section,illustrating the mirror enclosure of a single lens reflex camera and aparallelogram linkage system for raising and lowering the viewingmirror, together with a shock-absorbing mechanism embodying theinvention, the viewing mirror being illustrated in its viewing position;

FIG. 2 is a view similar to FIG. 1 showing the mirror in its raisedposition;

FIG. 3 is a perspective view of the shock-absorbing mechanism embodyingthe invention;

FIG. 4 is a side elevational view illustrating a second embodiment ofthe invention, the mirror being inits viewing position; and

' mounted on a shaft 2 secured to a wall of the box 1 is a substantiallyU-shaped member M which extends rearwardly and having pivotally mountedat its other end a stud shaft secured in the support plate 8 of theviewing mirror 9. The U- shaped member has two spaced arms-3, only onearm being illustrated, one on each side of the mirror, the ends of thearms,

or levers 3- as they shall hereinafter be referred to, being pivoted onshaft 2 at one end and a stud shaft 15 (only one shown) secured on theside of the mirror support plate 8. Pivotally mounted on a shaft 4secured in the box 1 is a drive lever 5, the other end of which supportsa shaft Sa'and intermediate its ends a pin 5b which is moved byconventional means (not shown) to raise the mirror 9, and lower thesame.

A connecting lever 6 is pivotally mounted at one end of the shaft 5a andat the other end on a pin 3a provided on lever 3. A second connectinglever 7 is provided also pivoted on one end on the shaft 5i: and at theother end on a shaft 8b provided on an extending arm 8a of the mirrorsupport plate 8. It will be noted that the levers 3, 6 and 7, and themirror support plate 8 form a parallelogram between their respectivepivot points.

Rotatably mounted on shaft 15 FIG. 3 on the support plate 8 is ashock-absorbing lever 10 provided on its free end with an extending pinl0a adapted to abut the lever 3. The pin 10a is also in the path of thesupport plate 9, as will hereinafter be made apparent. A coil springllsecured at one end to the lever and at the other end to a fixedretainer 15a on the shaft, biases the shock-absorbing levercounterclockwise in the direction of arrow B in FIG. 1, the pin 10aabutting the lever 3 when the mirror 9 is in its viewing or loweredposition.

A latch 12 for the shock-absorbing lever 10 is provided, the latch beingrotatably supported on a shaft 14 secured to the lever 3 adjacent theabutment point of the lever pin 10a. (FIG. 3). A spring 13 secured atone end to the latch 12 and at the other end to a fixed projection 14aof the pin biases the latch in a clockwise direction shown by the arrowC in FIG. 1. The latch 12 is provided with a bent portion 12a whichabuts a pin 16 secured to the mirror enclosure 1 when the mirror 9 is inits viewing position as illustrated in FIG. 1. A stop 17 is provided onthe mirror enclosure to limit the movement of the mirror in its viewingor lowered position and a second stop 18 to limit the upward movement orraised position of the mirror.

When the mirror is lowered by means well known in the art and not hereinillustrated, the latch 12 is rotated counterclockwise against the biasof the spring 13 by the abutment of the bent portion 12a thereof and theenclosure fixed pin 16. As will hereinafter appear, the latch 12releases the shock-absorbing lever 10 to permit rotation thereof in thedirection of the arrow B in FIG. 1 until the pin 10a engages the lever3.

ln the lowered or viewing position as illustrated in FIG. 1, movement ofthe pin 5b raises the mirror in the known manner, the mirror 9 beingmoved to its raised position against the stop 18 (FIG. 2) by theclockwise rotation of the drive lever 5 and upward movement of theconnecting lever 7. Lever 3 through the linkage provided by leve'r 6 isrotated counterclockwise about shaft 2.

As the mirror 9 moves upwardly, about halfway between its viewingposition and raised position, the mirror support plate 9 engages theshock-absorbing pin 10a. The continued upward movement of the mirrortoward its raised position will rotate the shock-absorbing lever 10clockwise against the bias of the shock-absorbing spring 1 1. With theupward movement of lever 3, the bent portion 12a of the latch 12 movesaway from the fixed pin 16 permitting rotation of the latch by itsspring 11 in a clockwise direction. A shoulder portion 12' on the latch12 thus moves into the path of the shock-absorbing lever 10 immediatelybefore the mirror reaches its raised position. The mirror 9 is thusmoved to its raised position against the stop 18, the latch 12 holdingthe shock-absorbing lever 10 in the raised position and preventing anyreturn movement of the mirror towards its viewing position by theshock-absorbing spring 1 1.

When the mirror is again moved to its viewing position preparatory tomaking another exposure, only the force of the drive lever moves themirror, the spring 11 being held inoperative by the latchingtarrangementdescribed. It is only toward the end of travel of the mirror to itsviewing position thatthe bent portion 12a engages the fixed pin 16. Thelatch l2is thus rotated counterclockwise to release the shock-absorbinglever whereupon it is returned by spring 11 to its position with the pin10a abutting the lever 3 as in FIG. 1. It should be noted that whatlittle shock there is upon release of the shock-absorbing lever 10 istransmitted to the lever 3 and not to the mirror support plate 8.

, Referring now to FIGS. 4 and 5 of the drawings wherein anotherembodiment of the invention is illustrated, the mirror enclosure or box101' of the camera is provided with a shaft 102 rotatably supporting asupport plate 103 for the viewing mirror 104. The mirror plate 103 isprovided with a pin 103a projecting into the path of movement of thetail portion 111a of a latch 111 pivotally mounted on a shaft 109secured to the mirror enclosure.'A spring 110 is provided for the latch,one end of the spring being hooked to the latch while the other is heldby a fixed pin 112. The spring 110 biases the latch 111 in acounterclockwise direction. A shock-absorbing lever 107 is rotatablymounted on a shaft 105 fixed in the enclosure, the lever being providedwith a pin 107a which extends into the path of travel of the mirror fromits viewing position against stop 113 to its raised position against astop 114. A shock-absorbing spring 106 fixed at the ends to the lever107 and fixed pin 108 rotates the lever in a counterclockwise direction,the

pin 108 limiting the counterclockwise movement of the lever.

A U-shaped lever (not shown in FIGS. 4 and 5) operated in the well-knownmanner and similar tothat illustrated in FIG. 1, for raising andlowering the mirror may be used; such lever being pivoted at one end onpin 103a with the other end pivoted to a shaft fixed in the mirrorenclosure.

'In raising the mirror from its viewing position illustrated in FIG. 4,the tail portion 1110 being freed of pin 103a permits counterclockwiserotation of the latch 111 toward its limit minor by the biased spring107.

Upon lowering of the mirror 104 to its viewing position, the latch tail111a is abutted by the support plate pin 103a just before the mirrorreaches its viewing position thereby rotating the latch in a clockwisedirection to release the shock-absorbing lever 107. The lever is rotatedclockwise by the spring 106 to its position against the stop 108. Whatlittle shock there is by this return movement is transmitted to the stoppin and not to the mirror or its support plate.

It will be obvious to those skilled in the art that appropriatefrictional means be included between the shaft and the shock-absorbinglever 11 of FIGS. 1 through 3, and similar means between the shaft 105and the shock-absorbing lever 1070f FIGS. 4 and 5, the frictional meansaiding the shockabsorbing effects of the springs 13 and 106.

There is thus provided a shock-absorbing arrangement for the viewingmirror of a camera in which the shock-absorbing springs provided have noeffect on the relationship of the mirrorraising spring after the mirrorsupport plate and the shockabsorbing lever abut during a liftingmovement by the mirror springs. Since the mirror completes its liftingmovement with the shock-absorbing spring latched, it is possible to makethe shock-absorbing spring quite strong and yet provide for a quick andcomplete return of the mirror to its raised position without shock andwithout noise. Since in a single lens reflex camera, the mirror israised aninstant before the shutter is released, the structures hereindescribed will prevent blurring of the exposures made due to mirrorimpact. By adjusting the bias of the spring 13 and spring provided forthe latches 12 and 107 further shock-absorbing effects may be realizedwhen the mirror is moved to its viewing position.

I claim:

1. Shock-absorbing mechanism for the viewing mirror of a single lensreflex camera having a mirror-operating mechanism for moving the mirrorbetween a viewing position and a raised position, the combinationcomprising:

a viewing mirror support plate pivotably mounted within the camera body;

a shock-absorbing lever pivotably mounted within the camera body;

a pin on the shock-absorbing lever extending into the path of the mirrorplate;

a first spring biasing the shock-absorbing lever in a direction oppositeto the direction of travel of the mirror from its viewing position toits raised portion;

a latch lever pivotably mounted within the camera body;

a second spring biasing the latch lever in a direction opposite to thebiased direction of the shock-absorbing lever;

a detent portion on the latch lever cooperating with the shock-absorbinglever;

a pin on the mirror plate abutted by the latch lever when the mirror isin its viewing position; and

movement of the mirror towards its raised position bringing about theabutment of the mirror and the shock-absorbing lever pin to move saidlever against the bias of the first spring; the latch lever, beingreleased by the movement of the mirror to its raised position, is movedby the bias of the second spring ,to bring the detent portion thereofinto latching position to latch the shock-absorbing lever immediatelybefore the mirror is moved to its raised position.

2. Shock-absorbing mechanism according to claim I,

wherein:

a U-shaped member having two spaced arms is pivotably supported at thespaced ends of the arms to the camera body;

the viewing mirror support plate being piv Jtally supported at theopposite ends of the U-shaped member arms, the shock-absorbing lever andthe latch lever being pivotably mounted on an arm of the U-shapedmember; and

means interconnecting the mirror plate with the mirror plate operatingmechanism of the camera to move the mirror plate between its viewingposition and its raised position.

3. Shock-absorbing mechanism according to claim 2, wherein a drive leveris pivotably mounted at one end to the camera body and movable by themirror-operating mechanism of the camera;

a first connecting lever pivoted at one end to an arm of the U-shapedmember and pivoted at the other end to the free end of the drive lever;

a second connecting lever pivoted at one end with the first connectinglever to the free end of the drive lever and pivotably connected at theother end to the mirror support plate; and

the two connecting levers and portions of the U-shaped member arm andmirror plate between the pivotal connections forming substantially aparallelogram linkage system.

4. Shock-absorbing mechanism according to claim 3, wherein the pivotpoint of the mirror support plate and the pivot point of the free end ofthe lever and the two connecting levers are on diagonally oppositecorners of the parallelogram linkage system.

'5. In a reflex camera having a mirror-operating mechanism for movingthe viewing mirror between a viewing position and a raised position, thecombination comprising:

a U-shaped member having two spaced arms pivotably supported at thespaced ends of the arms to the camera body,

' the viewing mirror support plate of the camera being pivotablysupported at the opposite ends of the arms;

a drive lever pivotably mounted at one end to the camera body andmovable by the mirror-operating mechanism of the camera;

a first connecting lever pivoted at one end to an arm of the U-shapedmember and pivoted at the other end to the free end of the drive lever;

- a second connecting lever pivoted at one end with the first connectinglever to the free end of the drive lever and pivotally connected at theother end to the mirror plate;

the two connecting levers and portions of the U-shaped member arm andmirror plate between the pivotal connections forming substantially aparallelogram linkage system for moving the mirror tween its viewing andraised position. I

1. Shock-absorbing mechanism for the viewing mirror of a single lensreflex camera having a mirror-operating mechanism for moving the mirrorbetween a viewing position and a raised position, the combinationcomprising: a viewing mirror support plate pivotably mounted within thecamera body; a shock-absorbing lever pivotably mounted within the camerabody; a pin on the shock-absorbing lever extending into the path of themirror plate; a first spring biasing the shock-absorbing lever in adirection opposite to the direction of travel of the mirror from itsviewing position to its raised portion; a latch lever pivotably mountedwithin the camera body; a second spring biasing the latch lever in adirection opposite to the biased direction of the shock-absorbing lever;a detent portion on the latch lever cooperating with the shockabsorbinglever; a pin on the mirror plate abutted by the latch lever when themirror is in its viewing position; and movement of the mirror towardsits raised position bringing about the abutment of the mirror and theshock-absorbing lever pin to move said lever against the bias of thefirst spring; the latch lever, being released by the movement of themirror to its raised position, is moved by the bias of the second springto bring the detent portion thereof into latching position to latch theshock-absorbing lever immediately before the mirror is moved to itsraised position.
 2. Shock-absorbing mechanism according to claim 1,wherein: a U-shaped member having two spaced arms is pivotably supportedaT the spaced ends of the arms to the camera body; the viewing mirrorsupport plate being pivotally supported at the opposite ends of theU-shaped member arms, the shock-absorbing lever and the latch leverbeing pivotably mounted on an arm of the U-shaped member; and meansinterconnecting the mirror plate with the mirror plate operatingmechanism of the camera to move the mirror plate between its viewingposition and its raised position.
 3. Shock-absorbing mechanism accordingto claim 2, wherein a drive lever is pivotably mounted at one end to thecamera body and movable by the mirror-operating mechanism of the camera;a first connecting lever pivoted at one end to an arm of the U-shapedmember and pivoted at the other end to the free end of the drive lever;a second connecting lever pivoted at one end with the first connectinglever to the free end of the drive lever and pivotably connected at theother end to the mirror support plate; and the two connecting levers andportions of the U-shaped member arm and mirror plate between the pivotalconnections forming substantially a parallelogram linkage system. 4.Shock-absorbing mechanism according to claim 3, wherein the pivot pointof the mirror support plate and the pivot point of the free end of thelever and the two connecting levers are on diagonally opposite cornersof the parallelogram linkage system.
 5. In a reflex camera having amirror-operating mechanism for moving the viewing mirror between aviewing position and a raised position, the combination comprising: aU-shaped member having two spaced arms pivotably supported at the spacedends of the arms to the camera body, the viewing mirror support plate ofthe camera being pivotably supported at the opposite ends of the arms; adrive lever pivotably mounted at one end to the camera body and movableby the mirror-operating mechanism of the camera; a first connectinglever pivoted at one end to an arm of the U-shaped member and pivoted atthe other end to the free end of the drive lever; a second connectinglever pivoted at one end with the first connecting lever to the free endof the drive lever and pivotally connected at the other end to themirror plate; and the two connecting levers and portions of the U-shapedmember arm and mirror plate between the pivotal connections formingsubstantially a parallelogram linkage system for moving the mirrorbetween its viewing and raised position.